Center drive lathe power chucking mechanism



June 14, 1949. w. R. MEYER ETAL I CENTER DRIVE LATHE POWER CHUCKING MECHANISM 9 Sheets-Sheet 1 Filed Dec. 5, 1945' INVENTORS. WAL 75/? R. MEYER m I BY HA ROLD J. S/EKMANN H ME r5 m v:

ATTGRNEYS.

June 14, 1949. w. R. MEYER ET AL 7 I CENTER DRIVE LATHE POWER CHUCKING MECHANISM I Filed Dec; 5, 1945' 9 Sheets-Sheet 2 IN VEN TORS I WALTER R. MEYER AND BY HAROLD J. SIEKMANN TLLW' L T-L-M' ATTORNEYS.

June 14, 1949. w. R; MEYER arm. 2,473,108

CENTER DRIVE LATHE POWER CHUCKINGMECHANISM Filed Dec. 5, 1945 9 Sheets-Sheet 3 3 a 9 ES II I I I IN VEN TORS. WAL TER R. MEYER BY HAROLD J. SIEKMANN *TQLML A rroqlys rs.

June 14, 1949. I w. R. MEYER ETAL 2,473,108

CENTER DRIVE LATHE POWER GHUCKING MECHANISM Filed Dec. 5, 1945 9 Shets-Sheet 4 INVENTORS. WALTER R. MEYER AND BY HAROLD J. S/E/(MA/V/V A TTORNEYS,

June 14, 19490 w. R. MEYER ET AL 2,473,108

CENTER DRIVE LATHE POWER CHUCKING MECHANISM 9 Sheets-Sheet 5 Filed Dec. 5, 1945 INVENTORS. WALTER R. MEYER AND HAROLD LS/EKMA/VN A T T ORNE Y8.

June 14, 1949.

Filed Dec. 5, 1945 w. R. MEYER- ETAL 73,10

CENTER DRIVE LA'I HE POWER CHUCKING MECHANISM 9 Sheets-Sheet 6 V INVENTORS. WALTER R. MEYER AND BY HAROLD J. SIEKMAN/V ATTORNEYS.

June 14,' 1949. w. R. MEYER ETAL 2,

CENTER DRIVE LATHE POWER CHUCKING' MECHANISM Filed D90. 5, 1945 v v 9 Sheets-Sheet 7 INVENTORS.

WALTER R. MEYER AND BY HA ROLD J. 8/5 KMA IVN A TTORNEYS.

June 14, 1949. w. R. MEYER ETAL 2,473,108

CENTER DRIVE LATHE POWER CHUCKING MECHANISM Filed Dec. 5, 1945 9 Shets-She t a PM: El

IN VEN TORS. WAL TE'R R. MEYER AND HAROLD J. S/EKMA/VN "MQQMS M ATTORNEY.

AUTOMATIC M ANU AL 2A6 June 14, 1949. w. R. MEYER ETAL CENTER DRIVE LATHE POWER CHUCKING MECHANISM Filed Dec. 5, 1945 9 Sheets-Sheet 9 Mum E ov vm N mum M 3 ad T QQM'WRD. A 32 s mm mu L R 0 S 2m /l k @E M fa SM Q rr 5 z Patented June 14, 1949 TENT OFFICE CENTER DRIVE LATHE POWER CHUCKIN G MECHANISM corporation of Delaware Application December 5, 1945, Serial No. 632,910

1 illaim.

pertains to machine tools and 1s partlcularly directed to improvements in crank- This invention shaft lathes. More particularly, this invention is directed to an improved power chucking mechanism together with coordinated operating and control mechanism to facilitate the loading and chucking of work pieces in center drive crankshaft lathes.

One of the objects of this invention is to provide an improved system of interlocked control for a center drive crankshaft lathe to more efliciently effect the loading, clamping, and machining of work pieces in the lathe.

Another object is to provide an improved power chucking mechanism for a center drive crankshaft lathe.

Still another object is to provide a method of loading and chucking a crankshaft in a center drive crankshaft lathe which requires a minimum of physical effort and thought upon the part of the operator of the machine.

A further object of this invention is to provide power chucking mechanism in the tailstocks of a center drive crankshaft lathe arranged to operate the work gripping the center drive work spindles of the lathe.

It is also an object to provide a novel arrangement for loading and power chucking a work piece or crankshaft in a double center drive crankshaft lathe.

And it is a still further object to provide an improved machine organization for a double center drive crankshaft lathe to facilitate the rapid loading. unloading. and accurate and positive chucking of the work in the lathe.

Further features and advantages of this invention will appear from a detailed description of the drawings in which:

Figure I is a front elevation of a double center drive crankshaft lathe incorporating the features of this invention.

Figure II is an enlarged fragmentary view of the right-hand tail-stock of the center drive lathe partly in section on the line IIII of Figures I and III.

Figure III is a top view of the tailstock indicated by the line 1II--III of Figure II.

Figure IV is a vertical transverse enlarged fragmentary section through the machine on the line IVIV of Figure I, particularly showing the construction of a tool carrier unit.

Figure V is a vertical transverse enlarged fragmentary sectional view through the machine on the line V-V of Figure I, particularly showing in."

and chucking devices in the construction of a center drive work spindle carrier unit.

Figure VI is an enlarged fragmentary diagrammatic section through the right-hand tailstock and the right-hand center drive Work spindle chuck mechanism indicated by the line VIVI of Figures II and V.

Figure VII is an enlarged fragmentary diagrammatic view through the left-hand tailstock and the left-hand center drive work spindle chuck mechanism similar to the View indicated in Figure VI.

Figure VIII is an elementary electric circuit diagram for the control mechanism of the machine.

Figure IX is the hydraulic circuit diagram of the operating mechanism for the machine.

General machine organization In the chucking of work pieces, such as crankshafts, having rough irregular webs which are to be gripped by the chuck jaws, difficulty is experienced in that the eqalizing chuck mechanism, which must necessarily be used under such conditions, must be properly and firmly clamped to the Work so that there will be no tendency for the work to slip in the chucks when heavy cutting operations are being performed on the work. This problem is particularly present when chucking a crankshaft in a double center drive lathe because the cutting forces applied to the Work in such a machine are extremely large. The loading of the crankshaft into the center drive work spindles also presents the problem of arranging the chucking members or work engaging members so as to allow axial insertion of the crankshafts in the center drive spindles prior to gripping them by the chucking mechanism. Definite limitations of the space in the center drive gears by the tailstocks and by the cutting tools which operate each side of and between the center drive chucks makes it difficult to provide adequate means for clamping the chucks to the work. Accessibility, therefore, becomes a paramount question which must be considered while at the same time allowing adequate clamping force to be applied to the chucking devices to firmly grip the crankshaft in the lathe.

Tailstocks must also be provided each side of the center drive work spindles which support the end portions of the crankshaft and initially position the work during the gripping of the crankshaft in the center drive chucks. Therefore, various problems of providing an adequate machine arrangement to facilitate the loading and considered. These problems are met by applicants,

machine organization and method of loading, unloading, and gripping the crankshaft in the chucks by the application of novel power operated mechanism coordinated and interlocked with. the cycle of machine operation.

As an exemplary disclosure of the specific application of this invention to machine tools, there is shown, Figure I, a double center drive crankshaft lathe comprising a base or frame to which is fixed a pair of center drive work spindle carrier units H and 12. Between these units is located the tool carrying unit l3 and on each side of these units are located the tool carrying units l4 and 15, all of which units are securely con-- neoted to the base l0 and interconnected with the sides of the center drive units H and i2 so as to form a solid block of metal extending across the lathe, flanked on each side by the side plate members 16 and 11..

Also mounted on the base each side of the center drive work spindle units H and i2 are the tailstocks I8 and I9, each of which has the reciprocatable center carrying slides 20 and 21 in which are mounted the respective work engaging centers 22 and 23.

In each of the center drive work Spindle carrier units H and I2 is iournaled the center drive work spindles 2d and 25, upon the periphery of which is provided the ring gears 26 which are connected through idler gears 21, Figures V and IX, to appropriate driving pinions 23 mounted on a common drive shaft 29 journaled in the center drive units H and I2. The drive shaft 29 is driven from the main drive motor 39 which drives through belts 3i suitable gearing, indicated generally at 32, Figure IX, which in turn rotates the drive shaft 29 so as to thereby drive the center drive work spindles 24 and 25.

Center drive chucks In the center drive spindles 24 and 25 are provided the chucking devices or chucks, Figures V, VI, and VII, for gripping the work piece or crankshaft W comprising a pair of swinging arms 33 and 34, each pivotally mounted on suitable pins 35 and 38 fixed to the work spindles. An actuating mechanism contained in the housing 3'? is connected through suitable pivotal connections 38 with the arms 33 and 34 and has an operating gearing 39 which may be actuated by wrench socket shafts so and M having wrench sockets 42 and 13 formed respectively in the ends of shafts All and 41. By the application of a suitable wrench to the sockets 42 and 43, the swinging jaws 33 and 34 may be engaged with or disengaged from the crankshaft or work piece W to firmly grip it and hold it on the axis of rotation A l of the lathe.

Loading, positioning, and chucking work M of the lathe and with the chuck operating sockets t2 and is positioned below said axis substantially diametrically opposite said openings '25. A crankshaft W is then placed on the righthand loading hoist hook 4b which is held in raised position by the loading, hoist mechanism indicated generally at M, which is of conventional design for such crankshaft lathes and operated by a motor Ma. The hoist 41 is arranged to roll horizontally on a suitable track or rail Mi fixed to the machine frame side members I5 and H by appropriate bolting means 69.

With the crankshaft W thus initially placed on the hook 3B,. the hoist t! is rolled horizontally to the. left on the. rail lil until it engages a stop screw 58. At this point, the crankshaft has been moved axially into the center drive work spindles 2d and 25 and is in the openings 45 of the center drive chucks. The motor Ma, Figures IV, V, and VIII, for the loading hoist 4! is then energized to lower the book 46 to present the crankshaft on the work supporting projections or work rest abutments and 5-2 formed integral with the respective chuck arm actuating mechanism housings 31. The hook 46 is then swung back out of the way and returned upwardly by reversely energizing the motor Ma and the hoist l'i is then rolled back to the right, withdrawing the hook from the center drive chucks.

When resting on the abutments 5i and 52 in the chucks, the axis of crankshaft W is slightly below the axis of rotation 44 of the lathe. In order to put the crankshaft exactly on center on said axis before gripping the crankshaft in the chucks, the crankshaft has been previously prepared with center holes in its ends which are engaged by the centers 22 and 23 thus lifting the crankshaft up off of the work supporting abutments 5i and 52 and exactly positioning the crankshaft on the axis of rotation of the lathe before the crankshaft is gripped in the center drive work spindles.

The preferred procedure in thus applying the centers 22 and 23 to the crankshaft comprises initially moving the center 22 carried in the tailstock slide 29 into the flange end of the crank shaft by rotating the hand wheel 53 of the left hand tailstock which is fixed on a shaft 54 suitably journaled in the left-hand tailstock housing I8 and has on its inner end a spiral gear 55 which engages a mating spiral gear 56 fixed to the actuating screw 5'! which is 'ournaled against axial movement in suitable bearings 58 in the tailstock housing 18. The threaded portion 59 of the screw 51 operates in a suitable nut 60 rigidly attached by screws 6| to the center slide 20, the slide being mounted in suitable guideways 62 in the tailstock housing H8. The hand wheel 53 is rotated until the center 22 has engaged the flange end of the crankshaft.

The right-hand tailstock center 23 is next engaged with the stub end of the crankshaft by applying fluid pressure to the cylinder 63 on the right-hand tailstock housing l9. Fluid pressure is applied in the chamber 6'! to cause the piston 64 and piston rod 65 connected to the tailstock center slide 2! to move in the guideways 66 of the tailstock housing Hi to move the center 23 into the stub end of the crankshaft W. With pressure thus applied behind the center 23, the crankshaft W is normally yieldably urged axially to the left in proper engagement with the center 22 and the operator finally adjusts the exact axial position of the crankshaft in the center drive work spindles by manipulating the hand wheel 53 and observing the usual centering gauge 68 which indicates when the crankshaft is properly positioned.

As soon as the crankshaft is thus properly positioned, both of the tailstock slides and M are rigidly locked or clamped to their respective tailstock housings l8 and I9 by fluid pressure clamping mechanism shown best in Figures II, III, and IX. Each of the tailstocks are provided with a clamp member 69 which engages a portion of one of the guide surfaces 66 of the tailstock center slides. A clamping bolt HI passe-s down through the clamp 69 and has a threaded end portion ll about which operates the clamping nut 72 which has an integral arm 13 connected through a pair of toggle links 14 and 15 pivoted together by a pin 16 and pivoted by a pin T! to the tailstock housing, as best seen in Figure III.

A hydraulic tailstock clamping cylinder 18 is rigidly fixed to the tailstock housing by suitable bolts !9 and has a piston 80 and a piston rod 8! connected by a suitable link 82 to the pin H5 at the middle of the toggle clamp arrangement. Thus, by the application of fluid pressure in the chamber 83 of the cylinder 18, the clamping nut 12 will thus be rotated so as to draw down the screw ill and the clamp 69 to lock the tailstock slides against axial movement in the guideways 68 in the respective tailstocks. After properly axially positioning the crankshai by manipulating the hand wheel 53 as described above, fluid pressure is applied in the respective pressure chambers 83 in the tailstock clamping cylinders 18 to firmly lock the centers in position for supporting the work piece during the machining operation,

After the crankshaft W has thus been initially positioned in the lathe on the axis of rotation 44, the chucking devices may now be engaged with the crankshaft webs for supporting and driving the crankshaft intermediate its ends. Each of the socket wrench shafts ll! and M for actuating the chucking devices is operated by a unique power mechanism or power chuck wrench contained in each of the tail-stock housings l8 and L9. This mechanism comprises an elongated quill 8'3 slidably mounted against rotation in suitable bearings 85 and 86 formed in the tailstocks is and i9. In these quills is journaled the drive shaft 87 on suitable bearings 238, the outer end of this drive shaft being provided with a splined wrench end as which may be moved axially into driving engagement with or disconnected from the sockets 42 and 43 of the chuck operating mechanism by reciprocation of the quills 84 in the tailstocks. Reciprocation of the quills is accomplished by manipulating the control lever-s 9i! and 9! carried on the rock shafts 92 journaled in the respective tailstock housings l8 and I9 and upon the inner end of which is fixed a pinion 93 engaging a rack 96 formed on the quill 84.

Driving power for actuating each of the drive shafts 8! and wrench ends 89 when in engagement with the chuck sockets 42 and 43 is provided by means of a hydraulic motor 85 having a shaft 85 which is connected to a gear 91 journaled in suitable bearings 93 carried on the tailstock housings l8 and I9 and which gear 9'! in turn drives a mating gear 99 similarly journaled on suitable bearings Hill carried in the tailstock housings. The gear 99 has a splined bore operating in driving engagement with the splined portion 31a of the drive shaft 81 so that driving relationship to the shaft 81 is maintained at all 6 times for any axial position of the quill 84 and th shaft 81.

When it is desired to clamp the crankshaft by the chucking devices, the control levers and ea are rotated respectively from positions 90a and Sla to positions 90b and Qlb, Figure I, so as to move the quills 8 toward the center drive chucks and engage their ends 89 with the chuck operating sockets t2 and 43. Appropriate fluid pressure is then applied to the motors to cause the drive shafts 8'1 to rotate and move the arms 33 and 34 to grip the crankshaft while centered by the centers 22 and 23 on the axis of rotation M of the lathe. After having thus gripped the work in the chucks, fluid pressure is released from the hydraulic motors 95 and the quills withdrawn into the tailstocks by appropriately moving the control levers 90 and Si back to positions 9% and 9m respectively.

The lathe is then ready for the machining operation to commence and the main drive motor 3% is energized to start rotation of the center drive work spindles 24 and The cutting tools T, best seen in Figure IV, then advanced to machine the desired surfaces upon the crankshaft W and, after the completion of the turning operation, the main drive motor is then deenergized and the work spindles automatically stopped. in a predetermined position of exact alignment of the chuck sockets 42 and is with the chuck wrench ends 89 of the drive shafts 81 and the quills a l of the power chucking mechanism in each tailstock.

Tool feeding mechanism Referring particularly to Figure IV, the tools T are carried on a pair of oppositely reciprocatable tool bars Edi and H32 carried in the tool carrying units [3, It, and Id. The lower tool bars i512 extend along the sides of the center drive chuck-s and in front of the chuck sockets 42 and 43. In order that the quills Bil may readily engage the wrench ends 89 to operate the chucks, there is provided a clearance opening or hole H33 in the lower tool bars Hi2 at each side of the center drive chucks so that the tool bars, when moved to retracted position, align the holes L3 for the passage of the quills through the tool bars I92 to engage the chuck sockets t2 and 43 for power clamping or unclamping of the work or crankshafts W.

The toolbars Edi and H52 may be oppositely reciprocatable in motion by a fluid pressure feed cylinder Hid, Figure IX, in which operates a piston m5 having a piston rod Hi6 connected through suitable rack and pinion mechanism it? to actuate the cam plate m8. This cam plate is mounted between the upper tool bars l8! and the lower tool it as best seen in Figure IV. Sui-table cam slots tile and lit in the cam plate its control the movement of the tool bars it'll and H82 through appropriate rollers Ill carried on pins i l2 fined in the tool bars. Thrust on the cam plate liiil in the direction of tool bar movement is absorbed by anti-friction roller means H3 and lid carried on suitable studs H5 fixed to the tool carrier units and center drive units 1 l, l2, l3, i i, and i5. It is to be noted that the cam plate i538 lies between the tool bars NH and H32 and moves in a direction normal to the direction of feeding movements of the tool bars and cutting movements. This arrangement provides an unusually rigid and efficient tool feeding mechanism for the machine which is free of vibration and chatter and is also simple in construction unive'rsalsirr its application. to effect any'dei-- sired type of feeding cycle required for the: cut:- ting tools.

Unchucking and unloading work After the completion of -the machining cycle and the chucks have stopped. in the position. indicated in Figures IV and V and. the tool: bars- IllI and IE2 have been retracted to: withdrawn position by the cam plate IBB by appropriately applying fluid pressure in the cylinder I04; the work'is'then ready tobe unloaded' from the. machine. The chucksare then unclamped by again manipulating the control levers 96 and SI to the respectivepositions- 9012'.- and: Sitb so as to again engage-the chuck sockets. 42 audit; The. hydraulic motors ilsare then operated in the reverse direction to unclamp the swinging arms 33 and 34 of the chucksrfrom. the crankshaft W. Having accomplished this, the levers 90 and 9| maybe left inpositions 9% and 9Ib for again; clamping a new workpiece in the chucks after the finished work piece has been. removed from the lathe.

The left-hand hoist II' EI is then moved" up against the stop I23: with its hook [41' project'- ing into the space 65 in the I centerdrive chucks; The hook It? is then: lowered by appropriately energizing the left-hand'hoist motor I Ilia, Figure VIII; so as toengage the: hook I'I'I' around" the crankshaft W; The centers 22. and 23' are retracted from the work by first. releasingthe' tailstock clamping mechanism by' applying fluid pressure in the chamber II 8 behind the piston 81) of the cylinder I8; Figure III, to release the toggle clamps and thereby release the tailstock center slides Eli and; ZI. Fluid pressure is then. applied. inv the chamber N9 of the right-hand tailstock slide actuating cylinder. E3 so as to withdraw the center 23 from the crankshaft. 'Ifhe; left-hand center 22 is then withdrawn by appropriately turning, the hand wheel 531 allowing the crankshaft to. drop down on the work rests 5I and.52.in the chucks.

Power isthen applied in a reverse direction to themoton I.I 6'a ofthe left-hand hoist IIE to raise its hook I I1). lifting. the crankshaft ofi. the Work rest abutments 5"I and'52'into the spaces 45. The left-hand hoist may then. be moved. from. the

spaces-45. to the left withdrawing the crankshaft outwardly. from. the chuckstov the unloading position. shown in Figure I; where the finished crankshaft is lifted from the hook.

General machine operation Summarizing the operation of the machine, the operatorfirst places the crankshaft W on the right-hand hoist hook 4B and moves the hoist into the'center drive chucks) to a predetermined position defined by the; stop. screw At this time, the center drive chucks are stopped with the loading spaces 45 positioned substantially above and to one side of the axis of rotation of the lathe. The crankshaft is then lowered to substantially aligned position with the work spindle' axis on work rests provided in the chucks. The work piece is then picked up by the centers and located in proper axialpositionandin proper alignment with: the work spindle axis. The power chucking mechanism. is then applied" to thechucks through the tool bars each side ofthe center drive chucks and operatively'engaging the chuck mechanism substantially diametrically opposite the loadingspaces- 45- provided for loading thacrankshaftinto the center drive chucks. The

alignmenttof: the. center drive. chucksi in 'a mode:- termined circumferential poistiont of stopping is done automatically'sol that the: power chucking mechanism in each" of the tailstocks may'automaticallyengagethechuck mechanism andclamp the-work in' the chucks. This contemplatesthe provision of; power chucking mechanism which may'pass through the lower toolrbars having passageways which also automatically align themselves: with the' power chucking. mechanism at the conclusion and stopping of the work cycle; And it is then thetprocedure to reverse this process in unloading the: crankshaft from the machine and preferably. utilizing a second loading hoiststo increase the=efiiciency and production of the machine:

Hydraulic operating. mechanism In order to operate the machine in the most efficient manner. it is preferable to utilize a hydraulic fluid pressure operating system illustrated in. the, diagram, Eigure IX. This system res ceilvesits sourceof fluid pressure from ahydraulic. fiuidJpressure. pump I.2I driven by a hydraulic pump motor 22.. The. pump IZ-I receives its supply of fluid. from thefluid reservoir I23 througha suction. line. I24 and transmits-pressure.intoathe pressureline I25.

Tailstock center operat ng mechanism.

The sequential movements of the right-hand tailstock center 23 b the cylinder 63 and the toggleclampsfor'the tailstocks as operated by the cylinders I8 is controlled by athree-position control valve I26 having a control lever I26d movable to positions IZBa, I261 and I260. When the control valve lever- I26d' is moved to the position 126a, the center 23' is retracted from the work crankshaft and the toggle clamps are released from the tailstock center slides 20 and 21 Under these conditions, fiuid'pressure from the line I25 passes through the valve 126 into the line I27, entering the pressure chambers Hi8 'of the cylinder [8 to release the toggle clamps, while the line I28 is connected through the: valve I26 to the drainv line I29 for return offluid to. the reservoir I23 from the=-chambers33 in the-cylinders I8. At the same time when theva'lve is in theposition IZE'a, fluid pressure from the line I25 is also connectedto line I38 which is connected to the pressure chamber II9- of the cylinder 63 so-as to cause Withdrawal ofthe center 23 while discharge fluid from the chamber 67 of the'cylinder 63 passes out through the line I SI, reliefvalve' I32; and the line I33, through the valve I26. into the drain line I29.

Whemthe lever I23d ismoved to position I261), the center 23zismoved into engagement with the crankshaft W While the tailstock slides-29 and 21 remain. unclamped so-thatthey may be moved in the tailstock while pressure is beingapplied in the chamber 6. of cylinder 63 by manipulation of the hand'wheel 53 as described. Under these conditions, fluid pressure from. the line. I25 passes through. the valve I26 into, the line I33, through the valve I32 and the line I3I into the chamber 6'! 0f the cylinder 83 while fluid is discharged from the pressure chamber H9 out through the line I30, through theval've I26 into the drain line I29. At-the same time, the toggle clamping cylindeisltl are'maintai'ned' in released position by fluid pressure being appliedifrom' the line I 25 through the valve I26 to the line I'Z'I', while. the line I28 is connected through thevalve. I26 to-the drain line I29... 'llhus position: I26bifor the valve lever I26'al serves for the initial axial adjustment of the crankshaft in the lathe by the hand wheel 53.

After the work has been properly positioned on the centers and in the center drive chucks, the valve lever l25d is then moved to the position I250, whereupon fluid pressure now passes from the line i25 through the valve 225 into the line I33, through valve I32 and line I3I into the cylinder chamber 31. A relief valve i3 connected into line I 3! together wi h the valve I32, both of which are connected to the drain line I29, serves to maintain the proper pressure behind the center 23 commensurate with the proper running engagement of the crankshaft on the centers and to prevent distorting the crankshaft during the initial engagement of the centers 22 and 23. The toggle clamps are also applied to lock the tailstock center slides 28 and 2| to their respective tailstock. housings I8 and It by fluid pressure which now passes throug'ii the valve l'ili into the line to the cylinders it While discharge from these cylinders passes out through the line it! and the valve 25 to the drain line i299, Thus, when the valve lever 525dis in this final position I26c, the centers have been properl engaged in the work and the tailsteck center slides rigidly clamped in the tailstock housings I8 and is.

Power chucking mechanism operation The hydraulic driving motors of the power mechanism. At this time the line I35 from this motor is connected through the valve I35 to the drain line l lo to effect rotation of the motor to drive the socks shaft ll of the left-hand center drive chuck to clamp the crankshaft therein.

The valve i also has a solenoid I ill which operates the valve so as to connect pressure from the line 525 to the line :359 and connect the return line from motor 95 through the valve 935 to the drain line I it to effect the reverse operation of the motor to unclarnp the chucking device in the left-hand center drive chuck.

In a similar way, the solenoid M2 of the other chuck operating control valve 535 when energized causes pressure to be connected through the line M3 to the hydraulic motor 95 of the right-hand tailstock while connecting the return line lit to the drain line I 35 through the valve I35 to effect clamping of the right-hand center drive chuck on the crankshaft. And when the solenoid M5 of the control valve I35 is energized, pressure will then be applied from the line l through the line ltd, while the line M3 is connected to the drain line I45 for unchucking the crankshaft in the righthand center drive chuck.

Spindle braking and stop operation In order to automatically control the slowing ment with the holes I03 in the tool bars HM and I52 and with the chucking quills in the tailstocks, there is provided a hydraulic braking mechanism comprising a control valve I41, Figure IX, actuated by a solenoid I48, the Valve receiving a pressure supply from the line I25. When the machine is started and operating in turning a crankshaft, the solenoid 18 of the valve I l-"l is de-energized while the solenoid I49 of a control valve E55 is energized. Under these conditions, a fluid pressure braking and stop motor I 5| connected to the shaft of the motor 30 will circulate fluid out through the line I52 directly through the valve i533 and return to the pump through the line I54 for free rotation of the pump I5I by the motor 30 While operating at full-rated speed during the cutting operation of the machine. The valve I53 will, at this time, be connected through a line I55 through the valve I to the drain line I29. The circuit between the braking motor I5I and the relief valve I53 is supplied by a supercharge pressure line I connected to the line I54 and receiving a pressure supply of a predetermined value through the pressure relief valve I5'i interconnecting the line I56 and the main pressure supply line I25, bypass of fluid from the relief valve I51 being connected to the drain line I29.

When it is desired to start the braking action to stop the .work spindles for loading and unloading the machine, the power is disconnected from the main drive motor 30 and the solenoid I as of the valve I 55 is ole-energized and the solenoid I ls of the valve I l? is energized. When the solenoid M9 is de-energized, the relief valve drain connection through the line I55 is blocked ofi', causing this valve to set up a restriction to flow between the lines I52 and I54 to thereby effect a braking action so as to restrict rotation of the motor 33 and slow it down. When the solenoid I58 of the valve I4? is energized, the outlet connection through the line I58 from the metering valve I 59 is connected to the drain line I29 through the valve I l? and the supply pressure from the line I25 is connected through the valve ISI, which is held open at this time by the braking back pressure through the line I62 so that this pressure is shunted around the valve IBI and through the check valve I 6Ia to the line I55. At this time, the hydraulic motor will decelerate with a braking torque equivalent to the pressure setting of the valve I53 until its speed is reduced to the point where the displacement of the braking motor I5I equals the flow setting of the valve I59. The braking pressure in the line I52 will then disappear, allowing the valve I6I to close so that the pump supply from the line I25 builds up pressure to drive the hydraulic motor l5! at a predetermined slow speed or jogging rate through the valve I5! and the line I55, fluid at this time passing through the line I62, through the valve I55, the line I58 through the valve I57, into the drain line I29. The pressure setting of the valve I5I is set slightly higher than the back pressure set up by the valve I59 so that the valve It! will remain closed during rotation of the hydraulic motor I5I and the main drive motor and work spindles connected thereto at the predetermined slow speed or jogging speed.

When it is desired to bring the work spindles and the driving motor 36 to definite stopped position for loading and unloading the crankshafts in the machine, both of the solenoids I58 and I59 of the respective control valves I57 and I50 are de-energized. This allows the valve It? to move to a position where all ports are blocked asthm so as to stop rotationof the hraking motor I I since the line I58fromthe-metering valve 159 is now positively closed off and the control line.I62 is also, closed off atthe valve I16l. Likewise, the lineI55 is closed offv by the .valve I56 atthistime. Themotor circuit, however, is continuously suppliedwith a reduced supercharged pressure from the line I56 through the valve I51 connected to the main supply lined 25 as, described to make upfor any leakage inthe braking motor It" and associated circuit.

When the solenoid M8 is de-energized and the solenoid I 49 is energized, the machine is in condition for full speed operation of the work spindles by the motor 39, the braking motor l5I in no way interfering withthe free rotation of the motor 39 at this time. When it is desired. toslow down the motor-top predetermined speed, or when it is desired to operate the work, spindles at a slow jogging speed with the main drive motor de energizedjn; both cases solenoid 146 is energized while solenoid I49 is dew-energized. (Finally, when it is desiredto-bring the machine to adefinite stop, both solenoids H8 and 149 are deenergized.

Work spindle positioning mechanism Associated with the above braking and stopping mechanism is an indexing or positioningplunger I14, Figure IX, for the center drive work spindles. The plunger I14 is actuated by a hydraulic cylinder I15 and engages a notch in a disc I16 fixed to the drive shaft 29 for the center drive gears 24 and 25. A control valve I11, receiving a pressure supply from the line I25, will connect pressure through the line; 618 to the cylinder- I15. to insert the plunger I14 into the notch in the indexing ,disc I16 as the disc rotates the notch into position of engagement by the plunger I14. This condition pertains when the solenoid I19, of the valve I11. is energized. .Returnof fluid from the cylinder I15 under these conditions passes out through the line 189 through the valve I11 into the drain line I29. When the solenoid I19 of the valve I1! is de-energized, pressure. will then be applied through the. line' I99 to Withdraw the plunger I14 from the notched disc ICI 6, while fluid is discharged from the cylinder i115 through the line I18 into the drain line I29.

Tool feeding operations ,The tool feeding mechanismof the lathe. which is actuated by the main feed cylinder: I04, Figure IX, is controlled in itsv various .feedand rapid travcrsemovements in both directions by a fluid pressure control valve mechanism I63 which receives its sourceof fluid pressure. supply from the pressure line I25. A forwardfeed pressure chamber I64 of the cylinder, I94. is connected through a line I85 tothe control valve mechanism I63 while the return. pressure chamber I66 of this cylinder is connected through a line I61to the control valve mechanism I63.

,A pair of operating and control, solenoids I68 and I69 are provided for thiscontrol valve mechanism I63. When it isdesired to rapid traverse the tools forward at the beginning oi a cutting cycle, both solenoids I68 and I69 I are energized. This applies, a rapid and large fiowof fluid pressure from the line tothe line Ito actuatethe piston in the cylinder 164 in forward rapid traverse movement while discharge from the cylinder HM passes out throughthe line I61, through the control valve I63 intothe drain line I29. To effect forward feedingmovement, solenoid 58 remains energized while the solenoid I69 is ole-energized so-that the control-valve I63 1 I-' duces the volume of flow through the lines I65 and I61 to thereby effect the reduced feeding movement to the cutting tools.

At the completion of the forward feed movement, rapid return movement of the tools isefiected by de-energizing solenoid I68 and energizingsolenoid I69 so as to adjust the valve mechanism I63 to now connect fluid pressure from the line !25 through the line I61 into the pressure chamber I66 of the cylinder Ilit while fluid pressure is discharged out of the chamber Hi4 and the line I65 into the drain line I29. When the tools are in retracted stopped position, both .solenoids !98 and I 69 are de-energized so as to cut off fluid supply from the pressure line I25 from both of the lines I65 and I61.

A supplemental rapid traverse movement under independent manual control may be effected by the control valve I10 having a control solenoid I1I which, when energized, connects a line I12 to the drain line I29. Under these conditions, fluid may escape from the line I61 through a metering valve I13 to the drain line 429 to effect a continuation of the rapid traverse movement after the rapid traverse movement has been stopped and the feed movement automatically instituted. The purpose of this arrangement is to permit the tools to be traversed in by the operator at an intermediate rate of travel between the normal rap-id traverse movement and the feed movement until the tools just begin to cut so as to attain a maximum output from the machine when great variation in the work piece necessitates be- I ginning the actual cutting at different radial distances relative to the work spindle axis.

Electrical control mechanism Preferably, the control and interlocking of the various machine functions and operations described above is most efliciently done by the utilization of electrical apparatus. In applicants present arrangement, the power lines I8I, I82, and, I83 for the electrical control system are connected by a main disconnect switch 184 with. a source of power indicated generally at 185 which supplies the main current for operating the main drive motor.36, the hydraulic pump motor ;I2 2 and lubricating pump motor I'22a and the loading hoist motors 41a and I I6a. In this particular instance these motors are three phase A. C. type connectible to the three phase power supply circuit comprising the lines I8I, I82, and I83. Control current for the electric control mechanism for the above motors and other control functions or" the machine is taken off through the primary leads I86 and I81 of a control circuit transformer having a primary winding 188 and an isolated secondary winding IBBa whose secondary is connected to the control leads I89 and I96.

The right-hand hoist motor 41a may be oper ated to lower the hook 46 to position the crankshaft on the work rests 5| and 52 by pressing the push button I9I' which completes the .circuit from lead I89 through lead I92, through normally closed contact 193a, lead I94, and contactor I to thelead E90, energizing contactor I95, opening control contact, I95a andclosing power. contacts I951), connecting the motor 41a to the power supply leads I8 I I82, and I83 to connect the motor to lower the hook 46. In order to raise thehook 46, push button I96. is pressed which completes a circuit from lead I89 through lead I91, normally v closed Control contact l95a,lead I98, contactor I93, to the lead I99, energizing contactor I93 to open control contact I93a and closing power contacts I931) to energize the motor 41a to raise the hook d6 of the hoist 41.

Similarly, pressing push button I99 lowers the left-hand hook II? by completing a circuit from lead I89 through lead 208, normally closed control contact 29in, lead 282, and contactor 203 to the lead I98, energizing the contactor 203 to eifect opening of the control contact 2030 while closing the power contacts 263?). In order to raise the left-hand hoist hook Hi, the push button 2S4 is pressed, completing a circuit, from the lead I88 through the lead 265, control contact 203a, lead 208, and contactor Zrli, to the lead I90, energizing the contactor 2M to open control contact 20Ia while closing the power contacts 20 lb.

Each of the operating motors 41a and IIEa for the work loading and unloading hoists is provided with a respective magnetic brake 41b and H61). When either of the motors 41a or Ilfia are energized, their corresponding brake is energized through leads filo and H50 so as to be released. When these motors are deenergized, the respective brake is also de-energized to brake and grip the motor shaft to prevent the load from overhauling and continuing rotation of the motors to thus quickly stop and hold the hoist hooks in any desired position.

The left-hand center drive chuck is clamped to the work by energizing solenoid I3'I oi the valve I35 by pressing the push button 261 to complete a circuit from the lead I89 through the lead 208, normally closed control contact 299a, lead 2I0, and relay 2| I, to the lead I20, which energizes relay 2 to open control contact 2I Ia and closes control contact 2IIb which completes a circuit from the lead I89, through the lead 2I2 and solenoid I-il, to the lead I90, energizing solenoid I31 to operate the valve I35 to connect fluid pressure to the motor 95 to clamp the left-hand chuck on the work. To unchuck the left-hand center drive chuck, push button 2 I 3 is pressed, completing a circuit from the lead I89, through the lead Zita, through the normally closed control contact 2IIa, and the lead 2%, through the relay 209, to the lead 590 to energize relay 209, opening control contact 299a and closing control contact 2H9?) which in turn completes a circuit from the lead I89, through the lead 2I5, through the solenoid IN, to the lead Hit, energizing the solenoid IM to operate the valve I35 to connect fluid pressure to the motor 95 to unclamp the left-hand center drive chuck.

In a similar way, pressing push button 2 I 6 completes a circuit from the lead I89, through the lead 2H, the normally closed control contact 2I3a, and the lead ZIEJ, through the relay 220, to the lead let, energizing the relay 220 to open the control contact 22% and closing the control contact 22Gb to thereby complete a circuit from the lead I89, to the lead 22l and the solenoid I42, to the lead I92, thus energizing the solenoid I42 to operate the valve I36 to direct fluid pressure to the motor 95 to eiiect clamping of the righthand center drive chuck. By pressing the push button 222, a circuit is completed from the lead ISQ, through the lead 223, the control contact 2220, and lead 224, through the relay 2I8, to the lead see, efiecting opening of the control contact 258:; while closing the control contact Zltb so as to complete a circuit from the lead I89 through the lead 225, through a solenoid I46, to the lead I88 to operate the valve I36 to cause fluid pressure to operate the motor 95 to unchuck the ri-ght-hand center drive chuck.

The hydraulic motor I 22 for operating the fluid pressure pump I2I is started by pressing the hydraulic pump start button 226, completing a circuit from the lead I39, through the hydraulic motor stop push button 221, lead 228, the lead 229, through the contactor 232, to the lead I99, thus energizing the contactor 230, closing the hold-in contact 230a so as to maintain the contactor 23h energized after the start button 226 is released. Energizing contactor 230 also closes contact 230!) which connects the lead I89 to the lead I890, to render the remainder of the spindle and feed control mechanism operative. The power contacts 2301: are thus also closed to connect power to the hydraulic pump motor I22. Fluid pressure is then being delivered to the hydraulic system from the pump I2 I. The hydraulic system may readily be rendered inoperative by pressing the hydraulic motor stop button 221 so as to de-energize contactor 23%, opening the hold contact 232a and also opening contact 23% to cut out the remainder of the spindle motor and feed electric control mechanism and opening poW- er contacts 2390.

With the hydraulic system operating by energizing oontactor 23%! as described, the main drive motor 323 may be started by pressing the run button 23! which completes a circuit from the lead I89! through the main drive motor stop button 232, the lead i851), through the limit switches 233, 234, 235, 2st, 231, and 238, to the lead 239, and the lead 246), through the relay 2M, to the lead I98, to thereby energize the relay 24!, providing all of the limit switches 233 to 238 inclusive are closed.

Limit switches 238 and 234 are closed only provided both of the respective loading hoists I I6 and ll have been moved to their extreme out positions to engage these limit switches on the rail 48 so as to prevent operation of the work spindles unless the hooks Ill and 16 are completely out of the center drive work spindles. Limit switches 235 and 236 are respectively closed by the control levers t0 and 9| when moved to positions 96a and Bio. of full retraction of the power chucking quills so that the work spindles can not be rotated unless the chucking quills are fully removed from engagement with the chuck sockets 42 and 33 and fully removed from the openings I03 in the lower tool bars I62. The limit switch 23? is associated with the positioning gauge 68 which engages the crankshaft W when adjusting the centers 22 and 23 as described and will only be closed when the gauge is swung back away from the crankshaft. The limit switch 238, Figure IX, is operated by the position of the locking plunger I15 and is only closed for rotation of the work spindle when the locking plunger is in retracted position away from the notched disc II'Ii.

Energizing relay 24! closes contact Z -Ha to energize relay 2 12. At the same time, contact we is closed. Contacts 2410 and 24M are respectively opened and closed. Energizing relay 242 closes holding contact 2 32a to maintain the relay 242 energized. At the same time, contact 22% is closed to energize relay 243. Contact 2420 is also closed by energizing relay 243. Relay 243 is thus energized, closing contact 2 33a and also closing contact 2 33b. The closing of contacts 22th and 2422) energizes the main drive motor contactor 2:34 which in turn closes the holding contact 244a to maintain the contactor 244 energized, which closes the power contacts 2441), connecting the main drive motor 30 to the power supply lines ISI, I82, and I33 Energizing contactor 2 3d opens contact 2 34c to de-energiae the braking and spindle positioning circuit when the main drive motor is being supplied with power. Also, when the main drive motor is running by energizing this contactor 244, contacts 24% and 25401 are closed to allow the tool traverse and feeding movements to take place.

With the main drive motor energized and: rotating the center drive work spindles, the machine may be set for either manual or automatic operation. Assuming the machine is set for manual operation by adjusting the selector switch 2&5 to the manual position connecting lead 266 with. lead 2M, the tools in push button 248 is pressed, completing a circuit from the lead I891) through the lead 2%, contact 25M, through the relay 2%, to the lead I39, so as to energize the relay 2 58, closing contact 258a to complete a. circuit from the lead S89, through the lead 25I, limit switch 252, lead 253, through the solenoid I'll of the manual traverse control valve 1m, and to thereby open thisvalve to effect the intermediate tools traverse in movement for the cutting tools.

' When the tools in push button is pressed, its associated contact 248a opens to maintain the relay 256 de-energized so that its contact 25411 remains closed and its contact 25% remains open. In order to continue th tools in movement under manual setting of the selector valve 2G5, the tools in button must be held depresse manually for the desired distance of tool travel. As soon as the tools begin to out on the work, the tools in button 2 28 is released. As the tools feed down to a predetermined relative position toward the work, a limit switch 252 is opened to de-energize solenoid Ill of the valve we so as to automatically prevent further manual infeeding as the tools begin to cut on the work. The trip dog 255 is adjusted to cancel the tools slow traverse in push button control at the innermost safe limit of possible engagement of the cutting tools with the work piece. The tools in buttonis then again pressed while the dog 255 continues to maintain the limit switch252. open but closing its contact 252a so as to energize the relay 250 to close contact 25% and thereby energize relay 253 which opens the contact 25% and closes the holding contact 2581) and also closes the contact 25cc which completes a circuit from the lead I89 through the lead 25? and the solenoid I53, to the lead I99, and also clcsesthe contact 256d, completing a circuit from the lead I89, through the lead 258, limit switch 259 and lead 2%, to the solenoid I69 so as to adjust the feed control valve I53 to cause forward rapid traverse movement of the cutting toolsto the work. The limit switch 259 is automatically operated by a dog 2SI subject to tool movement so as to actuate the limit switch 259 at a predetermined point of in movement of the tools so as to de-energize solenoid I69 of the control valve 53 to change from forward rapid traverse opens contact 2560 to tie-energize the solenoid The open-, ing of contact 25411 de-energizes relay 255 and I63} oi -the valve 163, the result being rapid tray,- ersereturn movement for the tools.

When it is desired to operate the machine inanautomatic cycle, the selector switch 245 is set in the automatic position. The operator then depresses the tools in button 2&8. and holds it depressed as the tools move in with both solenoids I68 and IE9 of the valve I63 and the solenoid Ill of the valve I'm energized for the rapid traverse movement to initial contact position of the tools with the work. The dog 255- then trips limit switch 252 andde-energizes solenoid IN to thereby cut out the manual rapid traverse and institute a slower rapid traverse movement. When the limit switch 259 is actuated by the dog 26L the solenoid I69 is de-energized, changing the toolmovement to slow feeding speed. At the end of the infeed movement of the tools, a dog 253. engages the limit switch 254, opening the connection between lead 2 and lead 24G=so that when a, dog. 266, carried by the rotating worktermined point ofv rotation of the workspindles determined by the circumferential position of the do 256 on the work spindles.

De-energizing the main drive motor contactor 244 closes contact 24%, completin a circuit through the run button contact 23Ia to the lead 268; through contact 2420 now closed, limit switch 2 36a now closed, normally closed contact 2690., and the relay 270 to thelead I98, to thus energize the relay 21!], opening contact 216a to de-energize relay 265i and to close contact 2701) and to close contact 216:: to energize the solenoid I48 ofthe valve 47 with the result that the braking motor l5I will decelerate the momentum of the main drive motor and Work spindles attached thereto as described. A contact 270d is also closed when the relay 2H3 is energized. As the main drive motor 30 decelerates to a predetermined slow speed, a zero speed control switch 2' closes its contacts at and below the predetermined desired speed setting for the-work spindles. Closing of the zero speed control switch 2'II renders a limit switch 212 effective so that when this limit switch 272 is actuated by a dog 2'73 carried by the rotating work spindles, the relay 2% will be energized which closes the holding contact 21 w and also closes the contact 2141) and the contacts 21 1c and 21%. The closing of contact 21421 energizes the solenoid 119 to move the positioning or indexing plunger I'M into the notched indexing disc Iltlwhilc the hydraulic braking motor I5I= is slowly rotating the main drive motor and work spindles at the predetermined slow jogging speed until the plunger drops in the index disc to accurately position the work spindles. When the lock pin goes in it opens limit switch 238 but power is held on the hydraulic motor until limitswitch 252a is opened by the tools backing out,

thus tie-energizing relay 210 to operate valve I4! closing contact 24Id momentarily in accordance with the movement of the jog button to energize or de-energize the relay 210 and thereby control the opening and closing of the contact 2100 and the operation of the solenoid I48 of the valve 14'! to supply fluid pressure to the motor ISI for operating the work spindles at the predetermined slow jogging speed.

When the main drive motor is again energized at the beginning of another work cycle, the relay 269 is energized by the closing of contact 2431), thereby closing contact 2690 so as to energize solenoid I49 and maintain it energized during the application of power to the main drive motor and, at the same time, contacts 269a and 2691) are opened so as to maintain the relays 21!] and 2'14 de-energized.

When it is desired to instantly stop the machine in an emergency to prevent damage or accident to the cutting tools and work, the stop button 232 is pressed, de-energizing contactor 244 to deenergize the main drive motor 30. De-energizing contactor 244 also opens contacts 2440 and 244d, de-energizing respectively the relays 256 and 25s] to bring the forward tool feeding and traverse movements to a halt. Tools out push button 262 may then be pressed to rapidly withdraw the tools by energizing the relay 254. By holding the jog button 215 depressed, the work spindles will be rotated by the hydraulic braking motor l5l at the predetermined slow jogging speed and the main drive motor and spindles then stopped at any point by immediately releasin the jog button.

In order to stop the spindles in the loading position, the jog push button 215 is held down and also the stop button 232 held depressed so as to close the stop button contact 232a so as to energize the relay 214 to insert the positioning or indexing plunger I14 and thereby stop the work spindles in the predetermined loading position. The jog button 215 is then released to bring the machine to rest.

As the cutting tools retract to withdrawn position and the limit switch 252 is relieved from contact with the dog 255, its contact 252a opens to thereby automatically de-energize the relay 210 which opens contact 2100 to de-energize solenoid I48 after the positioning plunger I14 has engaged properly in the indexing notch in the disc I16. It will also be noted that the normally closed contact 238a of the limit switch 238 will open when the locking plunger I14 is inserted after the final positioning of the work spindles so that the tools out relay 254 will be automatically energized to withdraw the tools at the completion of a work cycle and after the spindles have been brought to the predetermined loading position.

While the apparatus herein disclosed and described constitutes a preferred form of the invencapable of mechanical alteration without departing from the spirit of the invention and that such mechanical arrangements and commercial adaptations as fall within the scope of the appendant claim are intended to be included herein.

Having thus fully set forth and described this invention, what is claimed as new and desired to be secured by United States Letters Patent is:

In a center drive lathe having a base, a rotatable center drive spindle on said base, means for stopping said spindle in a predetermined position including driving means for rotating said spindle, a tailstock on said base, a tool feeding device on said base located between said spindle and said tailstock, a center in said tailstock located on the axis of rotation of said spindle, the combination of a chuck in said spindle having a work loading opening to one side of said axis to facilitate axial loading of a work crankshaft over said tailstock into or out of said chuck when the spindle is stopped in said predetermined position, an operating wrench socket on said chuck located below said opening and axis of rotation of the spindle when the spindle is stopped in said predetermined position, a power wrench mounted in said tailstock below said axis and movable parallel to said axis to engage said operating socket of the chuck, means for actuating said tool feeding device to and from a retracted position relative to said axis, and a passageway formed in said tool feeding device located so as to align itself with said operating socket and said power wrench when said tool feeding device is in retracted position to allow passage of said power wrench through said tool feeding device to engage said socket, and interlock mechanism operable by the movement of said power wrench into engagement with said socket to prevent rotation of said spindle by said driving means and the actuation of said tool feeding device from retracted position.

WALTER R. MEYER. HAROLD J. SIEKMANN.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,069,107 Groene Jan. 26, 1937 2,103,298; Pierle Dec. 28, 1937 2,141,466 Groene Dec. 27, 1938 2,191,935 Groene Feb. 27, 1940 ,215,922 Groene 1 Sept. 24, 1940 2,391,154 Groene Dec. 18, 1945 2,450,096 Siekmann Sept, 28, 1948 

